On the origin of interdecadal oscillations in a coupled ocean–atmosphere model

摘要: Interdecadal oscillations are analysed in a coupled ocean‐atmosphere model made of planetary geostrophic ocean within an idealized geometry, to zonally-averaged tropospheric atmosphere model. The interdecadal variability that arises spontaneously this system is caused by intrinsic dynamics, the air-sea feedbacks being not essential. spatial pattern bears some resemblance with observations and results obtained atmosphere-ocean general circulation models (AOGCMs) as well simpler climate models: large quasi-stationary upper temperature-dominated density anomalies found north-western part basin along weaker, westward propagating remaining interior. basic physical mechanism lies at heart existence mode large-scale baroclinic instability oceanic mean flow vicinity western boundary, characteristic forced constant surface fluxes. Freshwater associated hydrological cycle have only modest influence on mode. presence periodic channel mimicking Antarctic Circumpolar Current high southern latitudes prevents occur Southern Hemisphere.